You can do it with the Edit Top 200 Rows option.
When you go to that page, click on the button on the top bar that is a small square with the letters "SQL" in it. Hovering over the button it says "Show SQL Pane". Clicking on that button takes you to the query. You can change the TOP 200 to anything you want, as well as add a WHERE clause to the statement to filter results. Once you have changed the query to your liking, click on the red exclamation point button and it will run.
Now if you made your query properly you should see what you want to edit.
Another option is to change the default to Edit All Rows. You can do this by going to Tools -> Options. Then click on SQL Sever Object Explorer. You should see something like this:
Code:
Value for Edit Top <n> Rows Command 200
Just change the 200 to zero and click ok, and it will default to editing all rows.